316 research outputs found

    The largest white light flare ever observed: 25 April 1984, 0001 UT

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    The X13/3B flare of 25 April 1984, 0001 UT, was accompanied by intense white light emission that reached a peak power output approx 2x10 to the 29 erg/sec in the optical/near UV continuum; the total energy radiated in the continuum alone reached 10 to the 32 power ergs. This was the most powerful white light flare yet recorded, exceeding the peak output of the largest previously known event by more than one order of magnitude. The flare was a two-ribbon type with intense embedded kernels as observed in both Balmer-alpha line and Balmer continuum, and each of these flare ribbons covered separate umbrae shortly after the maximum of the event. The onset and peak of the white light emission coincided with the onset and peak of the associated E greater than 100 KeV hard X-ray burst, while the 1-8 angstrom soft X-ray emission reached its maximum 4 minutes after the peak in white light

    Critical Discourse Analyses of Early Education-Land Assemblages within Settler-Colonial British Columbia, Canada

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    ‘Outdoor’ education receives ample attention in early education, as land and dominant developmental discourses fuel promissory outcomes for children as future market driven citizens. What has not received sufficient attention are critical examinations of ‘outdoor education’ that account for persistent colonial-capitalist-neoliberal logics, especially in British Columbia, Canada where ‘outdoor’ education abounds. This thesis explores how early education perpetuates the ongoing creation of colonial pedagogies through a historical analysis of ‘outdoor’ education, and a Discourse-Historical analysis of the 2019 British Columbia Early Learning Framework (BCELF). Addressing three main discourses (quality, citizenship, and well-being and belonging), I underscore the need for anti-colonial efforts to seriously refuse enduring colonial-capitalist-neoliberal ‘outdoor’ program rhetoric and instead nourish just and equitable relations in land-based education

    Impulsive phase transport

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    The transport of nonthermal electrons is explored. The thick-target electron beam model, in which electrons are presumed to be accelerated in the corona and typically thermalized primarily in the chromosphere and photosphere, is supported by observations throughout the electromagnetic spectrum. At the highest energies, the anisotropy of gamma-ray emission above 10 MeV clearly indicates that these photons are emitted by anisotropically-directed particles. The timing of this high-energy gamma-radiation with respect to lower-energy hard X-radiation implies that the energetic particles have short life-times. For collisional energy loss, this means that they are stopped in the chromosphere or below. Stereoscopic (two-spacecraft) observations at hard X-ray energies (up to 350 keV) imply that these lower-energy (but certainly nonthermal) electrons are also stopped deep in the chromosphere. Hard X-ray images show that, in spatially resolved flares whose radiation consists of impulsive bursts, the impulsive phase starts with X-radiation that comes mostly from the foot-points of coronal loops whose coronal component is outlined by microwaves

    Imaging Spectroscopy of a White-Light Solar Flare

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    We report observations of a white-light solar flare (SOL2010-06-12T00:57, M2.0) observed by the Helioseismic Magnetic Imager (HMI) on the Solar Dynamics Observatory (SDO) and the Reuven Ramaty High-Energy Solar Spectroscopic Imager (RHESSI). The HMI data give us the first space-based high-resolution imaging spectroscopy of a white-light flare, including continuum, Doppler, and magnetic signatures for the photospheric FeI line at 6173.34{\AA} and its neighboring continuum. In the impulsive phase of the flare, a bright white-light kernel appears in each of the two magnetic footpoints. When the flare occurred, the spectral coverage of the HMI filtergrams (six equidistant samples spanning \pm172m{\AA} around nominal line center) encompassed the line core and the blue continuum sufficiently far from the core to eliminate significant Doppler crosstalk in the latter, which is otherwise a possibility for the extreme conditions in a white-light flare. RHESSI obtained complete hard X-ray and \Upsilon-ray spectra (this was the first \Upsilon-ray flare of Cycle 24). The FeI line appears to be shifted to the blue during the flare but does not go into emission; the contrast is nearly constant across the line profile. We did not detect a seismic wave from this event. The HMI data suggest stepwise changes of the line-of-sight magnetic field in the white-light footpoints.Comment: 14 pages, 7 figures, Accepted by Solar Physic

    Assessment of Hunger and Appetite and Their Relationship to Food Intake in Persons With HIV

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    Assessments of hunger and/or appetite are common methods of screening for development of illnessrelated anorexia. There are limited data to determine whether these methods predict actual food intake in persons with HIV disease. Therefore, the authors examined the relationship between self-reported food intake and subjective ratings of hunger and appetite in 31 adults with HIV infection. Participants also indicated presence of additional factors that can decrease amount of food eaten. Subjective ratings of appetite and hunger correlated with each other but not with food intake. Twenty-four additional factors that can affect food intake were reported to be present. The most common were illness-related and factors such as eating with friends or family. These results indicate that measures of hunger and appetite are not sufficient to screen for decreased food intake. Additional factors that can affect food intake should also be included in a comprehensive assessment of adults with HIV infection.http://deepblue.lib.umich.edu/bitstream/2027.42/69210/1/Assessment of Hunger and Appetite and Their Relationship to Food Intake in Persons with HIV Infections.pd
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